Isolation of benzylcellulose



; Patented ,July 29, 1930 UNITEDSTATES arr.

NT'QFFICEY EDUARD Donn, OF nnnnnrnnn, GERMANY, ASSIGNOR To I. G. {FAR'BENINDUSTRIE AKTIENGESELLSCI-IAFT, or FnAnKnoR'r-oN-THn-MAIN, GERMANY ISOLATION F BENZYL(313L131TLOSIE,Iv

No Drawing. Application filed September 20,1926, Serial nojme aa, and team s'lugust 17, 1$25.

The present inventionrelates to the isolation of benzylcellulose from crude benzylcellulose, more particularly it relates to the extraction of benzylc'ellulose from the crude 5 benzylcellulose obtained by the benzylation of cellulose. J V

In the benzylation of cellulose the crude benzyl cellulose is produced as a tough, gumlike mass containing benzyl alcohol and benzyl ether.

Hitherto, the Working up of this crude product has been eflected by extracting the reaction mass With solvents such as alcohol,

ligroin and the like, which dissolve benzylf alcohol and benzyl ether, but not the benzyl cellulose. y On account of the above mentioned consistency of the benzylated material, this process is difficult o1": execution, large quantities 1 of solvent being required in addition to the operation of kneading and involving a con-- Moreover by thlS,

siderable loss of time. means the benzyl cellulose is only obtained completely free from benzyl alcohol andvbenzyl ether with the utmost difliculty.

The present invention concerns the production ofbenzyl celluloses of a high degree of purity, and this new result obtained withv extreme ease by malaxating thetough pasty l mass for ashortztime with anywater-soluble salt,preferably an alkali Inetal-, oralkaline earth metal, salt, until a moist friable mass becomes available, in which form the benzyl celluloses are most suitable for the extraction. V\ henthis condition has-been reached, the

benzyl alcohol and benzyl ether, but not the benzyl cellulose, are dissolved out quickly and easily by means of a solvent,isuch as alcohol, benzine and. the like accordingto one of the well known processes, until the extraction liquid no longer contains'anybenzyl alcohol I or benzyl ether. Since the crude benzyl eel} lulose is distributed throughout the'mass in a tained as a-white flocculent product; i 1

According to an alternative method of working, the salt-containing mass only benz'yl alcohol or benzyl ether.

finely divided form,- this extraction takes" ing with" water.

extracted withlsolvent untilfonwashing out the intermixed salt, afiocculent product is obtained which no longer sticks together.

This product, however, naturally still contains a certain quantity of benzyl alcohol and benzyl ether, and the final extraction ofthese cellulose is well mixedwith common salt (i. e.,

a commercial grade of sodium chloride,') in amounts either equal or doubleby weight or more or less) and thenextracted Withbenzine in an extraction apparatus until theputflowing extraction liquid no longer contains any Thereupon the salt content of the mass is removed by washing with water; i

Example 2- 1 kilogram ot crude benzyl aiuniform consistency, 1 litre of alcohol is added andv the kneading is continued "for cellulose is malaxated with connnonlvsalt in amounts either equal or double by weight (or Zmore or less). -When the mass has assumed about /];42 an hourywhen the liquidis run off; If necessary, [the mass is extracted a second timeiwith 1, litre of alcoholfafter which the saltcontent is completely Washed out withwater and the final residu'es of ben- Zyl alcohol and ben'zyl ether are. then removed from the fiocculent product withcspirits.

The process can also bevaried by alter nately working withdifierent solvents, for example first with bent/line, then with ethyl alcohol or acetone, and lastly with Water.

This description contains subject matter described and claimedin application Ser. No. 260,240,filed March 8,1928. i i A Iclaim:* I 1. The improvement in the isolation of henzylcellulose from crude beniylcellulose obtainable by the benzylation of cellulose which comprises admixing with the crude benzylcellulose an inert water soluble salt, extracting the resulting mixture with alcohol and removing the residual salt by meansof wash- 2. The improvement in the isolation of henzylcellulose from crude benzylcellulose obtainable by the benzylation of cellulose which comprises admixing with the crude benzylcellulose common salt, extracting the resulting mixture with alcohol and removing the residua l sa'lt by means of washin withwater.

3. The improvement in the isolation of ben- Zylcellulose from crude benzylcellulose ob 10 .tainable by the benzylation oticel'lulo'se which comprisesladmixing therewith common salt, extracting the/separated cellulose with a mixture of alcohol and Water, removing the residual salt by means of washing With water and 15 extracting once more with alcohol.

' 4;. In processes for the isolationno f benzylcellulose from crude benzylcellulose obtainable by the benzylation of eelluloseinvolving the operations of admixing there'- 53 with common salt, extracting the resulting mixture with alcoholancl Washing out the residual salt by means of water; the steps which consist in carrying out the extraction I operation with a solvent comprising alcohol,

which is a non-solvent for the l'ienzylcellulose and a solvent for the impurities, to apoint Where, upon removal of the salt, the resulting product isfiocjculent and novlonger sticks together, removing the residual salt by means w ofs Washing with water, and extracting the resulting product with alcohol. 7 5. In the process for the isolation of henzylCellulose from crude benzylcellnlose obtainable by the benzylation of cellulose, the

;;,- 'step which comprises admixing with the V crude benzyl-cellulose an inert water soluble salt until a moist friable mass has formed. v

6. In the process for the isolation of hen-- zylcellulose from crude benzy'lcellulose obtainable by the 'benzylationrof cellulose, the it step which comprises admixing with the crude benzyl-cellulose' common salt until a .moist friable mass has formed. 2 I V In testimony whereof I have hereunto set my hand, 

